MELBOURNE, AUSTRALIA - JANUARY 19: Juan Martin Del Potro of Argentina plays a forehand in his third round match against Jeremy Chardy of France during day six of the 2013 Australian Open at Melbourne... more&nbsp

MELBOURNE, AUSTRALIA - JANUARY 19: Juan Martin Del Potro of Argentina plays a forehand in his third round match against Jeremy Chardy of France during day six of the 2013 Australian Open at Melbourne Park on January 19, 2013 in Melbourne, Australia. (Photo by Robert Prezioso/Getty Images) less&nbsp